Minimally invasive surgery (MIS) has allowed physicians to carry out many surgical procedures with less pain and disability than conventional, open surgery. However, unlike conventional open surgery, where the surgical site is readily accessible through a large incision, MIS typically requires the surgeon to operate remotely by inserting and manipulating instruments through small punctures, openings, or access sites in the body wall. A hollow cannula may be placed in the puncture to create a minimally invasive entry point. The cannulas, typically ranging in size from 5 to 20 millimeters (mm) are often sealed to maintain positive pressure within the peritoneal cavity to facilitate pneumoperitoneum during laparascopic surgery. One or more cannulas may be inserted into the body for any given operation. Medical instruments, such as grippers, manipulators, cutters, and suturing (sewing) devices are then inserted through the one or more cannula.
One of the more problematic tasks in MIS is suturing. Some surgeons use manipulators, such as needle drivers and gripping clamps, through an MIS entry point, as an extension of their hands in MIS suturing. Such techniques are time consuming and often require coordinated manipulation of multiple instruments. Given the limited space, limited visualization, and limited mobility in MIS, many surgeons find minimally invasive suturing by hand an extremely slow and difficult surgical task.
In response to the MIS suturing difficulties faced by surgeons, suturing devices have been developed to assist with and partially automate the rapid placement of suture stitches. Such devices often are available in a variety of sizes to fit through a corresponding variety of cannula openings. Larger MIS suturing devices can be effective in closing wounds because they are able to engage a larger bite of tissue for suturing, thereby enabling deeper suture placement within the tissue, and minimizing the likelihood that the suture will pull through the tissue. This can lead surgeons to choose larger cannula sizes, such as 10 mm or larger, in order to accommodate the larger suturing tools. Larger cannula sizes are associated with problems such as post-operative hernia formation or pain. Smaller cannulas, such as 5 mm, can lead to better patient outcomes including less peri-operative pain, rapid return of normal functions, earlier return to home and work, and reduced herniation risk. Unfortunately, currently available MIS suturing devices force a surgeon to trade-off between minimizing an invasive entry point size and maximizing suturing device effectiveness.
Therefore, there is a need for an efficient and precise minimally invasive surgical suturing device that enables surgeons to utilize small access sites without sacrificing the optimal larger tissue engagement features needed to enhance suturing effectiveness.